Pressure band for vulcanizing machines



J. M. BIERER PRESSURE BAND FOR VULCANIZING MACHINES June 8, 1937.

Filed May 26, 1936 Patented June 8, 1931 PATENT ori ce PRESSURE BAND FOR- VULCANIZING MACHINES John M. Bierer, Newton, Mass, assignor to Boston Woven Hose & Rubber Company, Cambridge, Mass, a corporation of Massachusetts Application May 26, 1936, Serial No. 81,839

5-- Claims. (Cl. 74-231) 'Ihis invention relates to machines for curing or vulcanizing sheetrubber or rubberized goods in which the operation is carried out by passing the goods about the circumference of a heated cylinder under the pressure of a continuous band. More especially theinventi'on consists in a wide, one piece pressure-exerting band of novel construction and having the capacity of operating under high tension. An important field of use of the the manufacture of rubberized belting, flooring, topping material and the like. In vulcanizing such goods the calendered material is maintained under severe-pressure beneath a steel band which travels about a portion of the circumference of the vulcanizing drum and is maintained under high tension to develop the requisite pressure. Heretofore the capacity of such machines has been limited in the width of the goods treated because it has been impossibleto produce steel tension bands in one piece of more than perhaps 22 inches in width. Accordingly, while manufacturers have been eager to produce such goods as conveyor belting up to 7-2 or 84 inches in width by a process of continuous vulcanization on a vulcanizing drum, it has been impossible heretofore to provide an adequate pressure band and wide goods of this character have therefore of necessity been vulcanized in step-by-step 0 manner inplate vvulcanizing machines.

The present invention rests upon my discovery that it is possible to build up a. composite steel pressure band from a plurality of band sections of high tensile strength united by welding along 7 their adjacent edges. In the preferred construction the band sections are of equal length and each made endless "by a transverse weld and are united along their longitudinal edges in such relation that the transverse welds are staggered by appreciable spacing. In a pressure band of v such construction the factor of safety does not depend on the strength of the transverse welds since their location is staggered in such manner that each weld is supported by the full strength' shown'in the accompanyin drawing in which,

invention is in Fig. 1 is a view in perspective of a complete. band shown more or less conventionally, and Fig. 2'is a view in perspective illustrating diagrammatically the manner in which the pressure band is used in a vulcanizing machine.

Fig. 3 is a view in perspective of a modified form of band. I v 7 As illustrative of the general type of vulcanizingimachine to which this invention relates, Fig.- 2 discloses a heated vulcanizing drum l0 and three guide rolls ll, l2, and I3 about, which is directed the steel pressure band I. The machine frame is omitted from the drawing for the sake of clearness but it will beunderstood that suitable bearings are. provided for the drum and rolls and that the bearings for the rearmost roll I3 are removable and urg d away from the drum l0 by hydraulic mechanism so that the band H is maintained at all times under'a severe tension.

The. lower guide rollfl2 is heated and the sheet material l5 to be treated is led to the drum l0 before it passes into the bight of the band I and there it is engaged between the circumference of. the drum l0 and one face of the band It. The material I 5 is thus maintained under heavy P essure during its travel about the drum and is vulcanized under conditions of heat and.pressure compact sheet.

From the foregoing explanation it will be apparent that the band I must be of great strength, perfectly smooth and of uniform thickness in order that it may run smoothly in the machine. The overall width of the band herein shown nay be assumed, for purposes of illustration, to be 84 inches and to be made up of four endless sections A, .B, C, and D each 21 inches an integral homowelds A, B',, C', and D. .Any commercial buttwelding method may be employed, such as the oxy-acetylenemethod in which an oxy-acetylene flame is applied to adjacent edgsreducing them to a molten condition-in whichthey will fuse together, additional steel-l being supplied from a weldingrod. In Fig. 1a freshly formed' and also molded by this treatment into a smooth 7 and D'ar'e independently '5 band, and the completed band is then ."subjected' to heat treating or tempering;

It is important to locate the transverse welds A B, C, and D in longitudinally staggered relation and as herein shown the transverse welds in adjacent sections are separated by substantially halfthe band length and are thus supported on both sides by the full strength of both adjacentsections. An-important characteristic of the band of my invention is its smooth continuous surface, this being required in order to produce a smooth faced vulcanized product. Attempts have been made heretofore to-operate with a lap-welded band but this has not proved practicable since any surface irregularity in the band is transferred to the vulcanized product.

Another important characteristic of the band of my invention is its strength. In order to secure the severe pressure necessary to the suc- 2 cessful vulcanizing process a tension as high as to 40 tons is required in the hand. These -requirements are too severe to permit the employment of commercial sheet steel but necessitate a high carbon steel having a tensile strength 30 of from 160,000, to 300,000 lbs.'per square inch.

It is these exacting requirements that are successfully met by the present invention with the result that the capacity of continuous vulcanizing machines is increased far beyondanything heretofore possible and wider and more perfectly vulcanized goods are made available in the market.

While it is preferable for reasons already pointed out to unite the band sections with 40 their transverse'welds in staggered relation, it

is practicable to locate the transverse welds close together or even to align them transversely v in the belt. It is also practical, under some conditions, to construct the pressure band of a series of transversely arranged band sections buttwelded together without. longitudinal seams.

SuchabaridisillustratediriFiB-3 ofthe drawing-and comprises a series of sections ll of flat sheet steel stock of high tensile strength and of a length equal to the width of the band.- 'lhese sections are united by edge to edge welds-.2. into an integral unit of uniform thicknessandare groundandpolishedtopresentasmooth and ,continuous work-engaging surface throughout thefacethatistoeontactwiththevulcanialng' drumil or theimaterlal pressed thereon. Since a composite pressure band ofthistype for use in a vulcanizing machine is a new article .in the industry, 'various modifications of structural detailsmaybe madewithin thescope ofthein It will be apparent that in both forms of the invention. as herein illustrated and specifically vdesci'ibeihthse'bandcornprisesaseriesoi'rela- -06-tivelynarrowsectionsofflatsheetsteelstockof high tensile strength welded in edge to edge re- -lationinto an integral; unit of uniform thickness throughout and its work face disposed wholly in'a single plane on both sides of the welded joints and across said joints.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is,

1. For a vulcanizing machine, a wide, endless tension band comprising a plurality of longitudinal steel sections of equal length each made endless by a transverse'butt-weld, the sections being butt-welded together along their 10M- 10 tudinal edges, the respective transverse welds being staggered longitudinally with appreciable spacing and the bandas a whole presenting a smooth continuoussurface.

2.'l"or a vulcanizing machine, =.a'wide,' end- 15 less pressure band comprising-a series of, endless steel sections each having a transverse weld therein and being integrally-united to adjacent sections by longitudinal welds, the transverse welds being staggered with the maximum spac- 2o ing permitted by'the number of sections and the length ofthe band andthe band as a whole presenting a continuous polished surface.

3. A wide endless tension band for use in a vulcanizing machine having a vulcanizing drum 25 against asubstantial arcuate portion of which the band is adapted continuously to press vul-V canizable material held therebetween as the band under tension moves along with the drum, the band comprising a plurality of endless rib- 3 bon-like steel sections of high tensile strength, narrower than the band and of equal length and thickness, welded in edge to edge relation into an integral unit. of uniform thickness on both sides of and across thewelded edge-toedge joints, and having one face lying wholly in a single plane on both sides-of and across said joints.

4. A wide endless tension band for use in a vulcanizing machine having a vulcanizing drum against a substantial arcuate portion of which the bandis adapted continuously to press vu1-' canizable material held. therebetween as the band under'tension moves along with the drum, the band comprising a series of relatively narrow sections of flat sheet steel stock of high tensile strength welded in edge to edge relation into an integral unit of uniform thickness throughout and havingone face disposed wholly in a single plane on bothsides of its welded joints and across said joints.

5. A wide endless tension band for use in a vulcanizing machine having a vulcanizing drum against a substantial arcuate portion of whichthe band is adapted continuously to press vul canizable stock held therebetween as the band under tension moves along with the drum, the bandcornprising a series of relatively narrow' sections of flat sheet steelstock of high tensile strength and of a length equal to the width of the band, welded in edge 'toedge relation into an integral unit of uniform thickness and on opposite sides of and across the welded edge-toedge joints and having one face disposed wholly in a single plane on both sides of said joints 

